i have bought some cisco ip phones model: 7914g i have updated to sip protocol via tftp. but i have a 3rd party sip provider whos details i cannot enter to make the phone work. what do i do

HI, i am having major difficulties with the Cisco phone 7941g. i have been able to successfully update the phones to sip via tftp. i have a 3rd party sip provider and i would like to make this phone work with there service. but i can figure out how t...